Artefact in imported Hair
Apologies as I'm kind of new, so I'm unsure how to fix all of your issues, but I assume the bump is an issue with colliders, as a similar thing happened with one of my models.
Try editing the collider for the head by moving it or making it smaller. This should at least partially help with the weird hair lump. I removed the hair in my screenshot to make it more easily visible, but this specific collider seems to give a lot of issues if you go directly to blender.